Introduction: Circulating very long-chain saturated fatty acids (VLSFA) are biomarkers of diet and metabolism which impart different biological activities to sphingolipids and may influence physiological pathways relevant to aging. Higher levels of circulating VLSFAs have been associated with lower risk of all-cause mortality, cardiovascular outcomes, and diabetes. Apart from these associations, it is unknown whether these biomarkers are related to the maintenance of healthy aging.
Hypothesis: Higher levels of circulating VLSFA are associated with lower risk of unhealthy aging.
Methods: Phospholipid fatty acids were measured in serial plasma samples collected among participants of the Cardiovascular Health Study (CHS) in 1992-93, 1998-99, and 2005-06. Incident unhealthy aging was defined as the onset of cardiovascular disease (CVD), cancer, lung disease, severe chronic kidney disease, ≥1 difficulties with activities of daily living (ADL), or reduced cognitive function (Mini-Mental State Examination<80). We assessed the associations of arachidic acid (20:0), behenic acid (22:0) and lignoceric acid (24:0), with risk of incident unhealthy aging using Cox regression with time-updated fatty acid levels and covariates.
Results: Among 2,183 CHS participants with one or more fatty acid measure and healthy aging up to the time of their first VLSFA measurement, mean age at baseline was 75 years, 62% were female, and 12% were black. During median follow-up of 8 years, all but 198 participants failed to age successfully. The most common conditions marking the first occurrence of unhealthy aging were ADL difficulties and CVD (27% each). In analyses adjusted for major risk factors, higher levels of 22:0 and 24:0 were associated with lower risk of unhealthy aging (Table).
Conclusions: Higher levels of two circulating VLSFA, 22:0 and 24:0, are associated with lower risk of unhealthy aging. These findings open a new avenue of research into these saturated fatty acids and their possible beneficial role in promoting better aging.